Frequently Asked

Cement, lime
& climate change

Limiting global temperature increase and mitigating the worst effects of climate change represents one of humanity’s greatest challenges. The cement and lime industries are amongst the largest industrial contributors to climate change, accounting for approximately 8% of global CO₂ emissions. Unlike other industries, most of the CO₂ produced in the manufacture of cement and lime is released directly and unavoidably from the processing of limestone, an abundant and widely available raw material.

From essential infrastructure like buildings and roads to applications in steel, pharmaceuticals and agriculture, cement and lime provide the foundations of our societies and economies. They are indispensable to our way of life. Even if a higher diversity of materials are used in the future, cement and lime will continue to be indispensable to meeting infrastructure demands and ensuring global living standards continue to improve in the transition to a carbon neutral world.

To preserve our way of life, cement and lime producers must urgently decarbonise at the lowest possible cost. As penalties for emitters increase across the world, decarbonising is not only a matter of environmental responsibility for producers. It is a matter of survival.

Cement and lime are both made from the processing of limestone to form quicklime (calcium oxide). For cement, additional processing with a second, clay-containing material is required to form clinker and finally cement.

Lime is used in the iron, steel, paper, pharmaceuticals, food, farming and chemical industries. Cement, which is approximately ten times the size of the lime industry, is the key ingredient in concrete, the most widely used man made substance on Earth.

Calcination is the heating of a chemical compound to high temperatures to remove impurities or cause thermal decomposition. The most common application of calcination is the heating of limestone (CaCO₃) to remove carbon dioxide (CO₂) and produce quicklime (CaO).
Process emissions refer to emissions released directly from the chemical processing of raw material. They are inherent to the chemical reaction and distinct from energy related emissions that may result from the consumption of fuel to heat the reaction. For cement and lime, the processing of limestone results in the direct and unavoidable release of carbon dioxide as a process emission, accounting for approximately two-thirds of the total CO₂ emissions in the cement and lime industries.

Cement and lime production is the largest single industrial contribution to climate change, responsible for approximately 8% of global CO₂ emissions.

The Paris Agreement, signed by 192 countries in 2016, committed to limiting the global average temperature increase this century to 2 °C above pre-industrial levels. Signatories also agreed to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels.

Globally, there are currently 73 carbon pricing initiatives, covering 23% of global emissions. While regulations vary across jurisdictions, within Europe, most industries’ CO₂ emissions are regulated under the EU Emissions Trading System (EU-ETS). The ETS is a cornerstone of the EU’s policy to combat climate change and its key tool for reducing greenhouse gas emissions cost-effectively. This mechanism sets a cap on the total amount of greenhouse gases that can be emitted, with the total number falling each year.

Within the EU-ETS cap, companies receive or buy emission allowances, which they can trade with one another as needed. Although cement plants have received ‘free’ allowances in Europe based on benchmarked performance, these free allowances are now being phased out following the introduction of the EU’s carbon border adjustment mechanism (CBAM).

Carbon dioxide that is captured and safely and permanently stored according to the EU legal framework will be considered as ‘not emitted’ under the ETS. Cement plants that do not stop their CO₂ from reaching the atmosphere need to surrender allowances for each tonne of CO₂ released.

While there are not yet regulations regarding atmospheric emissions at a federal level in the USA, there are incentives for CCUS in the form of the 45Q tax credit and its significant enhancement under the Inflation Reduction Act.

Carbon Capture, Utilisation
& Storage (CCUS)

Carbon capture is the process of selectively removing and capturing carbon dioxide (CO₂) from industrial processes. Captured CO₂ can then be used in further industrial processes or permanently stored.

The cement and lime industries are highly emissions intensive. Unlike other industries, however, most of the CO₂ produced in the manufacture of cement and lime is released directly and unavoidably from the processing of limestone. Carbon capture is the only means by which unavoidable process emissions can be prevented from reaching the atmosphere and contributing to climate change.

To date, carbon capture technologies have typically been developed by or adapted from the energy sector for enhanced oil recovery (EOR), amongst other uses. Many of these projects have proven largely uneconomical, due to a combination of high capital and operational costs, insufficient incentives to capture CO₂, and the emergence of less carbon-intensive alternatives.

All other carbon capture technologies rely on separating gases from gases, which requires energy and results in higher costs. Leilac’s novel approach, however, delivers a breakthrough in carbon capture technology, as it keeps the CO₂ released from the process pure, without the need for a gas separation step. It will efficiently and economically capture process CO₂ emissions in cement and lime production.

After being captured, industrial CO₂ emissions are compressed and transported to their end use or storage location. Approaches to transport, use and storage of CO₂ are not industry specific and can be developed for use by all CO₂ emitting industries and utilities.

Carbon utilisation consists of a range of technologies that use or convert CO₂ to make valuable fuels, feed, chemicals, building materials or other products. Cement and lime producers are constantly expanding their utilisation efforts and only rely on storage if the CO₂ cannot be used elsewhere.

Today, the primary means of ensuring that the CO₂ generated by industry does not reach the atmosphere is to permanently store or sequester it, mainly because of the available capacity. The storage of CO₂ for process related emissions from ‘hard-to-abate’ industries is recognised widely as a necessary technology to reach the Paris Agreement. Geological storage of CO₂ has been safely undertaken for many years. From storage in deep saline aquifers, to depleted hydrocarbon fields, to mineralisation where the CO₂ is bound to rocks, geological storage of CO₂ uses well established, regulated, effective and safe practices.


Leilac stands for Low Emissions Intensity Lime And Cement.

The Leilac technology is designed to enable the efficient capture of unavoidable process emissions that are released directly from limestone or cement meal – with no additional chemicals or processes – and to be compatible with renewable energy sources and clean alternative fuels.

Leilac’s indirectly heated calcination technology works by simply re-engineering the existing process flows of a traditional calciner to keep the furnace exhaust gases separate from the reaction products. By doing so, this unique approach ensures process emissions remain pure and can be simply and efficiently captured as high purity CO₂.

Leilac’s technology aims to operate on a variety of energy sources, including electricity and alternative fuels, Leilac should be able to also rapidly switch energy sources to enable grid load balancing and enhanced economic operations.

If a carbon based fuel is used, Leilac can work with any viable post-combustion capture technology to deliver a dual capture approach to total plant emissions. This approach can enable significant cost synergies. With Leilac capturing the majority of the host plant’s emissions, the remaining emissions resulting from fuel use can be captured by a relatively small post combustion plant that can be powered primarily by waste heat.

Together, Leilac’s fuel optionality and compatibility with post-combustion capture provide viable, flexible and economical pathways to carbon free cement and lime.

Leilac’s technology aims to be compatible with a variety of energy sources, including electricity and alternative fuels, enabling the full decarbonisation of lime and cement.

Leilac also seeks to enable rapid switching of energy sources, allowing a very large industrial plant to use excess (or peak) electricity from variable renewable electricity sources and deliver grid stability. Ultimately, the electrification of heavy industry and the flexible use of alternative energy sources can enable the broad deployment of renewable generation, without the need for additional intermittent generation from fossil fuel power stations or the capital and efficiency costs of large scale energy storage.

Leilac’s projects are the application and demonstration of the Leilac technology.

Leilac’s unique technology was first applied to the production of cement and lime at the Leilac-1 pilot plant, located at project partner Heidelberg Materials’ (formerly HeidelbergCement’s) plant in Lixhe, Belgium. Operating since 2019, Leilac-1 has successfully demonstrated efficient separation of CO₂ process emissions for cement and lime.

Leilac-2, due for construction in 2024, is a modular retrofit design that will be integrated into the Heidelberg Materials operational plant in Hanover, Germany. Leilac-2 is designed to capture about 100,000 tonnes/year of CO₂ emissions from a commercial scale cement plant, and demonstrate the use of alternative and renewable fuel sources. Leilac-2 is designed as a replicable module that can be simply scaled to a cement plant of any size.

To learn more about the Leilac projects, please visit our projects page.

Leilac has worked with and been supported by numerous partners in industry, academia and government in the development and implementation of its industry leading technology. Together, we are creating sustainable cement and lime for industry, global society and our planet. Together, we are accelerating the transition to a carbon neutral world.

Leilac-1 partners are Heidelberg Materials (formerly HeidelbergCement), CEMEX, Lhoist, PSE, Quantis, Tarmac, The Carbon Trust, TNO and Imperial College London. They collectively contributed €9m, in addition to €12m in grant funding as part of the European Union’s Horizons 2020 programme.

Leilac-2 partners are Heidelberg Materials, CEMEX, BGR, The Centre for Research and Technology Hellas, CIMPOR-Indústria de Cimentos, ENGIE Laborelec, The Geological Survey of Belgium, ENGIE Laborelec, IKN GmbH, Lhoist, Politecnico di Milano and the Port of Rotterdam. They are collectively contributing €17m, in addition to €16m in grant funding as part of the European Union’s Horizons 2020 programme.

We recognise and thank each of our partners for their vital contribution of industry expertise and resources towards the urgent and sustainable decarbonisation of global cement and lime.

The Leilac Technology Roadmap to 2050 provides cost-effective pathways to carbon neutral industrial production of cement and lime. You can view the Roadmap here.

For more information about Leilac, our technology, projects, or the decarbonisation of cement and lime, please contact us.

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